1. Field of the Invention
The present invention relates to a camera which has a zoom lens and a function for designating a print aspect ratio of a print concurrently with photographing, and more particularly to a camera wherein an effective angle of view of an effective picture area to be used for printing is maintained substantially constant, so as to maintain the condition of a primary subject within the effective picture frame substantially unchanged before and after changing the print aspect ratio or the focal length.
The invention also relates to a method of automatic framing in the camera.
2. Related Art
Recently, there have been 35 mm full-size format compact cameras which can take pictures in a panoramic size from which a panoramic print can be made. For example, "Cardia Travel Mini" (a trademark) is one such compact camera.
In such a variable-exposure-opening-type camera, pictures are usually taken within an exposure area that corresponds to a full-size frame, 24 mm.times.36 mm in size (aspect ratio 1.5). However when a panoramic print is desired, a pair of mask plates are inserted in an exposure opening corresponding to the full-size frame, so as to mask out the upper and lower portions of the exposure opening and provide a horizontally extended exposure area 13 mm.times.36 mm in size (aspect ratio about 2.8).
An original taken in this panoramic size is printed at a magnification which is about twice the magnification used for making a standard size print from the full-size original frame, thereby making a horizontally extended panoramic print.
The conventional variable-exposure-opening type cameras are provided with a frame display device in a view-finder for showing a photographic field that corresponds to the frame size so as to show the selected aspect ratio, during framing. On the other hand, if print size data are magnetically or photographically recorded on photographic film during photographing, and a photographic printer can read the print size data from the photographic film, it is possible to eliminate the mask member and make a panoramic print from the 24 mm.times.36 mm full-size original frame, by trimming or clipping the original frame to leave a 13 mm.times.36 mm panoramic area when the print size data read by the photographic printer designate the panoramic size. Only the 13 mm.times.36 mm area is printed at a higher magnification, thereby making a panoramic print. This fixed-exposure-opening-type camera has an advantage that no frame size changing member such as an LCD mask is necessary.
However, many types of recent compact cameras employ a zoom lens as the taking lens, and if the above-described print size designation function is incorporated in such a zoom camera, a problem would arise, namely, if the photographer first performs zooming so as to set a primary subject in a desirable size in a scene, and thereafter, designates the panoramic print size, the primary subject may vertically exceed the height of the panoramic print. In such a case, if the photographer still wishes a panoramic print, the photographer must perform zooming again, while referring to the display in the viewfinder, so that the whole portion of the primary subject desired to be taken is included within the range of the panoramic print. This is obviously cumbersome.
The just-described problem would be still more complicated if the zoom camera is provided with a print aspect ratio designating function, by which various print sizes having different aspect ratios, such as HDTV size (aspect ratio about 1.8), cinemascope size (aspect ratio about 2.3) and panoramic size (aspect ratio about 2.8) can be designated besides the standard size (aspect ratio 1.5). In this case, if the photographer wishes to give priority to zooming and designates secondarily an aspect ratio, it is necessary to select another appropriate aspect ratio by operating a print aspect ratio designating device after zooming. The framing operation becomes still more cumbersome.